Protection and Control Challenges of Low-Voltage Networks with High Distributed Energy Resources Penetration - Part 1: Utility Workshop and Low-Voltage Network Modeling

The growing distributed energy resources (DER) penetration in the low-voltage network (600V and below) challenges the existing protection philosophy and practice. To assess the impact of high DER penetration, the authors built a representative low-voltage network model in real-time electromagnetic transient software and performed hardware-in-the-loop (HIL) protection studies. In the first stage of the effort, the authors invited four major U.S. utilities with low-voltage networks to a technical workshop to survey the modeling and study needs. Guided by the workshop discussions, the authors developed various real-time simulation models, including a low-voltage network model, a model of a commonly used network protector relay, and DER models. Finally, the authors conducted hardware-in-the-loop protection studies to investigate and mitigate the high DER penetration impacts. Part 1 of the paper summarizes the technical workshop outcomes and low-voltage network modeling approaches. Part 2 of the paper reports the HIL simulation setup, high DER penetration impact assessment, and benchmark results of a promising mitigation solution.